Robotic cleaning devices have been developed to automatically clean environments with minimal assistance or control from a user. To help with navigation, robotic cleaning devices typically include sensors that allow detection of obstacles in an environment. For example, some robotic cleaning devices include touch sensors that are activated when the robotic cleaning devices bump into an obstacle.
Some cleaning robots use floor-type detection techniques as a trigger for autonomously altering various floor-cleaning characteristics, as described in U.S. patent application Ser. No. 14/622,613. In particular, a flooring type can be determined as a function of a signal from a motion sensor indicative of a change in pitch caused by a cleaning robot crossing a flooring discontinuity. In other examples, the flooring type is determined based on a power draw signal corresponding to a cleaning head assembly of a cleaning robot.
Other cleaning robots determine to alter direction in response to a reflected signal indicating an edge of a floor surface, as described in U.S. patent application Ser. No. 14/511,947. In particular, such cleaning robots include multiple pairs of signal generators and sensors disposed at different locations about a peripheral edge of the cleaning robot, and where a controller is configured to alter the cleaning robot's direction as a function of which sensor receives a reflected signal indicating a floor surface edge.
Other cleaning robots determine a floor type based on output from a surface type sensor, as described in U.S. patent application Ser. No. 10/798,227. The surface type sensors described previously include an optical detector, ultrasound detector, or a mechanical detector. However, these types of detection systems have only been described at a high level, and not with any kind of specificity that would allow a person of ordinary skill in the art to determine the floor type based on the surface type sensor.